IEffectFog

This abstract interface controls distance fog settings. Settings for this interface can influence the choice of shader permutation. This interface is implemented by BasicEffect, AlphaTestEffect, DualTextureEffect, EnvironmentMapEffect, NormalMapEffect, and SkinnedEffect.

Obtaining the interface

There are two methods used in DirectX Tool Kit. For simple cases, just maintain a reference directly to the desired effect class:

std::shared_ptr<BasicEffect> effect;

...

effect->SetFogEnable(true);
effect->SetFogStart(6);
effect->SetFogEnd(8);
effect->SetFogColor( Colors::CornflowerBlue );

For more general cases where a number of effect classes can be in use (such as Model which uses a mix of BasicEffect, DualTextureEffect, SkinnedEffect, and/or DGSLEffect), use Run-Time Type Information (RTTI) to obtain the interface.

std::shared_ptr<IEffect> effect;

...

auto ifog = dynamic_cast<IEffectFog*>( effect.get() );
if ( ifog )
{
    ifog->SetFogEnable(true);
    ifog->SetFogStart(6);
    ifog->SetFogEnd(8);
    ifog->SetFogColor( Colors::CornflowerBlue );
}

Fog

The fog effects work for both right-handed and left-handed coordinate systems, but the distance settings should be negated for left-handed coordinates.

Built-in Effect Notes

BasicEffect, AlphaTestEffect, DualTextureEffect, EnvironmentMapEffect, NormalMapEffect, SkinnedEffect

These implement a simple linear fog which is inexpensive on all feature levels.

DGSLEffect

Fog settings are encoded in the choice of DGSL pixel shader, if supported, and these shaders do not expose settings to control such effects. Therefore, this built-in effect does not support this interface. The default materials (Unlit, Lambert, and Phong) have no fog effects.